Johnny G Pipe

Hi folks, I think my CCU is playing up for the first time..perhaps it was only a matter of time.

So, with the car running, no interior fan will come on if I turn the fan speed dial.

If I start the engine with it turned on, say to '3'..it blows for a second or 3, and then stops. Rapid defrost button doesnt work either..

I have checked fuses in Frunk, and swapped what I believe is the blower relay with its twin sitting next to it with no change.

Anyone had this happen, any suggestions? A temporary voltage surge on starting getting past a dying connection is my best guess..

Cheers

boxsey911

Blower relay is in the rear fuse box but it sounds like you have the classic symptom of the blown fuse for the blower which is also in that rear fuse box. It's a 30 amp fuse but might be a 25 amp if it was the original (Porsche changed the rating later on). There are only 3 fuses in the box so you'll easily know which it is.

J richard

On all my 964 the hvac switches are sketchy. I would try it and when it quits wiggle the fan speed and the AC push buttons and see if the fans come back on.

GBX

i pulled the CCU out, cleaned the connections and it fixed a similar problem.

ducnine

Did you ever hear a whistle sound when you had your fans on? If so it could be the bearing in the squirrel cage fan in the frunk area (Usually the one on the passenger side). If the bearing is starting to seize, then you will hear the whistle and eventually the fuse will blow. I think its a 25amp fuse in the frunk fuse box. This is what is happening on my car. I changed my R12 over to R134 and it was blowing cold air for a while before this started happening.

Johnny G Pipe

Thanks friends..no squeaky noise before this but that could be the problem. A general case of OCS..old car syndrome.

Will check out the suggestions and report back, cheers.

martin964

I had this issue, the problem was a loose wire in the connection to the rear heater blower.

the blower is engaged as soon as you turn the dial off 'cold' and as boxey says is a large current (hence the big fuse). once the connection had warmed up, or I had wiggled it to the right place the heater blower worked, which in turn let the front fans work. this was then fine until the next cold and damp day.

I now have a new car which has had the blower motor removed but I have the same symptoms... I will check the relay etc. but I suspect a bad conection.

porsche mania

The problem with your new car isn't a bad connection, this happens to all cars when the bypass pipe is fitted. They don't tell you this when you order one! I'll bet if you turn the temp control right down the fan kicks back in? It's a simple fix that's well documented on here. A jumper cable to supply a small power supply to where the relay would have been is all that's needed.